Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f820c1e48bd0023…

MALICIOUS

PDF

68.9 KB Created: 2021-09-26 18:50:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 4a1bf40d8d5315910187d30dc579d804 SHA-1: d74ccbe256876c1e0984ccce8e93fe18b86ef9cd SHA-256: 4f820c1e48bd00239871da0195509fd6a55da758553db926a82dc79e43faa9df
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate the document functions as a link farm, directing users to multiple external websites, some hosted on compromised CMS uploads. The presence of numerous PDF link farm indicators suggests an attempt to distribute malicious content or conduct phishing operations.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://hohsingfiber.com/ufiles/files/zuwibulifaberijamuwewo.pdf In PDF document text
    • https://otoform.com/upload/ckfinder/files/rubalunuponokarapom.pdfIn PDF document text
    • http://aquitaine.annuaire-regional.com/ckfinder/userfiles/files/45803324495.pdfIn PDF document text
    • http://huile-de-nigelle.info/userfiles/file/58307460965.pdfIn PDF document text
    • https://ubranni.com/uploader/files/59143718120.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/acc55e2b2d6a2376dabb4a8b7e89a68f/lapowevijodi.pdfIn PDF document text
    • http://bsa-billiard.by/images_from_html_editor/file/telipinorabupoz.pdfIn PDF document text
    • http://ecocj.com/userfiles/file/20210922214839.pdfIn PDF document text
    • https://creativesilhouettes.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16147d2713bd20---vigexalararedikep.pdfIn PDF document text
    • http://goodfortune.hk/UpLoadFile/file///fejisiw.pdfIn PDF document text
    • https://www.techsrollout.com/wp-content/plugins/formcraft/file-upload/server/content/files/16145b61b0490a---69271501307.pdfIn PDF document text
    • http://travelcenterpuntos.com/campannas/file/jegareparutivik.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161434ef12e22f---82002728458.pdfIn PDF document text
    • http://pro-roubenky.cz/UserFiles/File/25939544154.pdfIn PDF document text
    • http://marktoby.com/akram/know_news/admin/userfiles/file/lobunagazukekuwogoraduse.pdfIn PDF document text
    • https://sowlindia.com/userfiles/file/26477815048.pdfIn PDF document text
    • http://fosterfreezesantarosa.com/uploads/files/wemiwimigunilibugukawoniz.pdfIn PDF document text
    • https://vendax.ro/files/file/81334908954.pdfIn PDF document text
    • https://istanajp.com/contents/files/19331601790.pdfIn PDF document text
    • https://ncfouting.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130597aa0641---10845859251.pdfIn PDF document text
    • http://tuanlongland.com/upload/files/66566919226.pdfIn PDF document text
    • http://ergakiland.ru/files/files/86967494300.pdfIn PDF document text
    • http://hoanggiaphatland.com/uploads/image/files/416880554.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/c04760d2402fda736bc155029253dec8/73874703021.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=bubble+pop+game+online+freePDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b001.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB001 10728 bytes
SHA-256: 37882dce5fc6c0180aa9ce6f230c04ca4811a9fa2adec29e09b6dcacef8e7a56
font_01_sfnt_off0000c856.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC856 14940 bytes
SHA-256: f8ef712c764dbe03516003f55812732278d6eb65a9e6bd9b6727363fa82e59b9
font_02_sfnt_off0000edf1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDF1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1